Drill-bit.



G. W. MGALLISTER.

DRILL BIT.

APPLIGATION FILED JUNE 23, 1913.

Patented Mar. 23, 1915.

F R Z INVENTOR.

DRILL-BIT.

Specification of Letters Patent.

Patented Mar. 23, T9 15.

Application filed June 23. 1913. Seria No. 775,356.

To all whom it may concern:

Be it known that T, GEORGE WATSON Mo- ALLIs'rER, a citizen of the UnitedStates, residing at San Francisco, in the county of San Francisco andStatev of California, have invented a new and useful Drill-Bit, of whichthe following is a specification, in such full and clear terms as willenable those skilled in the art to construct and use the same.

This, invention relates to a rotary drill bit for deep drilling. The bitis intended to operate either in ground where a core is to be produced,or to produce the hole and to break the core as the drilling proceeds,

should that be desired.

An object of. the invention is toproduce a drill bit which will becapable of maintaining a hole of a given diameter for as great a depthas possible in rock'and to furnish as great a length of cutting edges aspossible, thus giving the bit a long life.

Another object of the invention is to produce a drill bit which will bein a measure self-sharpening, so that it will not be necessary to removethe drill bit from the hole until .a considerable depth has beendrilled, the object being to practically wear out the bit beforeremoving it from the hole.

A further object of the invention is to produce a bit which will havethe cutting portions thereof so inclined with respect to the axis andperiphery of the bit as to continuously maintain a substantially fixedcutting angle.

Another object of the invention is to produce a bit capable ofdelivering and discharging the water used in the drilling operations tothe cutting edges without forcing the same up the hole outside of thedrill and rods, should that be desired.

An embodiment of the invention is shown in the drawings in which thesame reference numeral is applied to the same portion throughout, but Iam aware that there are many modifications thereof.

Figure 1 is a side elevation of a bit constructed in accordance withthis invention, a portion of the bit being broken away for purposes ofillustration, Fig. 2 1s a plan view of said bit, Fig. 3 is a verticalsectional view of the bit shown in Fig. 1, Fig. i is a horizontalsectional view of thebit shown in Fig. 1, Fig. 5 is a vertical sectionalview of a portion of a bit similar to the one shown in Fig. 1 withsuitable core breakers connected therewith, Fig. 6 is a horizontalsectional view of the bit shown in Fig. 5, Fig. 7 is a side elevation ofthe bit in which the hard segments project beyonl the softer-segments,Fig. 8 is a horizontal sectional view of the bit shown in Fig. 7 as thesame would appear without core breakers, and Fig. 9 is a horizontalsectional view of the bit shown in Fig. 7 with the 'core breakersapplied thereto I The numeral 1 represents the softer portion of acylindrical drill rod, said rod being threaded as indicated at 2 andhaving a cen-' tral opening 3 and two side openings 4:. The numeral 5indicates spiral segments of a hard steel such as manganese or chromesteel, which segments are connected with the alternating softer spiralsegments 6 by a suitable process such as the electrical or 'thermit.

In order to give the drill a start in the be ginning the hard segmentsare extended down below the soft ones as indicated in Fig. 1 a shortdistance so that by the time the hard portion has worn awa the softersegments will have received su cient wear to leave them in shape forcontinuing the cutting operations.

Inasmuch as it is intended to supply and discharge the water used in thedrilling operations through the drill itself, the top of the drill isprovided with a groove 8 to permit the water from an attached drill rodtopass into said outer openings even though the openings in the bit andadjoining drill rod are not accurately alined. It will, of course, beunderstood that the outer openings 4: are formed in the softer segmentsof the drill bit.

The bit just described is adaptedfor the production of a core where itis desired to remove the core from the hole without breaking the same.When it is desired to destroy the core as the hole is drilled the bitshown in Figs. 5 and 6 is used. In this form the segments extendspirally around the bit substantially the same as the bit shown in Fig.1, as indicated at 10 and 11.

The bit shown in Fig. 5 has openings 12 in the soft segments andembedded in others of the soft segments are the core breaking cutters 13to 18 inclusive. These core breakers are so placed as to graduallyscrape off the outer portion of the core, the upper breakers extendingnearer the center of the core than the lower ones, so that as the drillpasses downwardly it will gradually disintegrate the core formed andpermit it to be forced to the surface with the water passing up thecentral opening.

'In the form of the bit shown in Figs. 7, 8 and 9 spiral segments 19 and20 are used, the segments 19 extending beyond the segments 20 as far asis deemed necessary to carry on the drilling operations in the givenground, Whether hard or soft. The drill shown is provided with but asingle opening and has no core breakers so that a core would be producedthereby and the water used in drilling would pass down inside the drilland up the outside thereof. However, this drill may be equally well usedfor the purpose of breaking the core and carrying the same to thesurface for sampling if desired.

Fig. 9 represents a bit of precisely the same outside appearance as thatshown in Fig. 7 but with the hard segments 21 and soft segments 22, twoof the soft segments having holes 24 therein while two of the other softsegments have the core breakers 25 embedded therein. In this latter formof the invention the hard segments 21 project bevond the soft segmentsas much as may be deemed necessary for cutting the given ground.

Having thus described my invention what.

I claim as new and desire to secure by Letters Patent of the UnitedStates, is as follows, modifications within the scope of the claimsbeing expressly reserved:

' 1. A bit for rotary drills comprising a rod having means at one end tosecure an adjacent drill rod thereto and cutting means at the other end,said rod being formed of a series of alternating hard and soft spiralsegments, substantially as described.

2. A drill bit for rotary drills comprising a drill rod havingalternately hard and soft spiral segments, said hard spiral segmentsextending beyond the periphery of the softer segments, substantially asdescribed.

3. A drill bit for rotary drills comprising a rod having means at oneend to secure the same to an adjacent drill rod and having cutting meansat the other end, said bit being composed of a series of alternatelyhard and soft segments, the hard segments extending beyond the peripheryof the soft segments for their entire length, substantially asdescribed.

4. A bit for rotary drills comprising a rod having an openingtherethrough, said rod being threaded at one end and composed nsasaea ofa series of spiral alternating hard and soft segments, substantially asdescribed.

5. A bit for rotary drills comprising a rod having a plurality ofopenings therethrough, one of which openings is central, and said rodbeing composed of a plurality of longitudinally extending alternatinghard and soft segments, substantially as described.

6. A bit for rotary drills comprising a rod having a plurality ofopenings therethrough, one of which openings is central, said rod beingcomposed of a series of alternately hard and soft spiral segments, and aplurality of core breaking cutters embedded in the softer segments andextending into the central opening, substantially as described.

7. A bit for rotary drills comprising a rod having a plurality ofopenings therethrough, one of which openings is central, said bit beingcomposed of a series of alternating hard and soft spiral segments, and aseries of core breaking cutters embedded in the softer segments andextending toward the center of the central opening through the red, theupper cutters extending nearer to the axis of the drill bit than thelower cutters, substantially as described.

8. A bit for rotary drills comprising a rod having means at one end tosecure an adjacent drill rod thereto and having cutting means at theother end, said rod being composed of a series of alternately hard andsoft segments, the hard segments extending beyond the periphery of thesofter segments, substantially as described.

9. A bit for rotary drills comprising a rod having means at one end tosecure an adjacent drill rod thereto and having cutting means at theother end, said rod having a plurality of openings therethrough, one ofwhich openings is central, and being composed of a series of alternatelyhard and soft segments, the hard segments extending beyond the peripheryof the softer segments, and a plurality of cutters embedded in the'softsegments and extending into the central opening toward the axis of thebit, substantially as described.

In testimony whereof I have hereunto set my hand this 10th day of JuneA. D. 1913, in the presence of the two subscribed witnesses.

GEORGE WATSON MOALLISTER.

